1 Growth Curves

Length/Weight

The relationship between length and weight for these species is expressed by \(W=a*L^b\)

Age/Length

The von Bertalanffy growth curve was used to find the relationship between age and length using K and Linf as argument \(Linf*(1-exp(-k*t)\) for the following species.

1.1 Pollock

1.1.1 Length/Weight

The relationship between Pollock length (cm) and weight (lbs). The data was collected during NEFSC research bottom trawl surveys from 1992 to 1999. For the autumn surveys which were conducted from Cape Hatteras, North Carolina to Nova Scotia, Canada where, a= 0.000007244 and b= 3.1151 (Wigley et al., 2003). Winter/Spring surveys were conducted from Cape Hatteras, North Carolina to the Southern Flank of George’s Bank, where a= 0.000006788 and b= 3.1024 (Wigley et al., 2003).

1.1.2 Age/Length

The relationship between Pollock age (yrs) and length (cm) calculated by the von Bertalanffy growth rate for Nova Scotia, Canada where K= 0.1 and in the Northwest Atlantic, Canada where K= 0.17 (Erzini, 1991). These growth rates are compared to commercial fishing data gathered from 1976 to 2018 as well as survey data gathered by NEFSC.

1.2 Red Hake

1.2.1 Length/Weight

The relationship between red hake length (cm) and weight (lbs). The data was collected during NEFSC research bottom trawl surveys from 1992 to 1999. For the autumn surveys which were conducted from Cape Hatteras, North Carolina to Nova Scotia, Canada, a= 0.000005976951 and b=3.0162 (Wigley et al., 2003). Winter and spring surveys were conducted from Cape Hatteras, North Carolina to the Southern Flank of George’s Bank (Wigley et al., 2003). For the winter surveys a= 0.000006788 and b= 3.1024 (Wigley et al., 2003). For the spring surveys a= 0.000004225 and b= 3.0979 (Wigley et al., 2003).

1.2.2 Age/Length

The relationship between red hake age (years) and length (cm) calculated by the von Bertalanffy growth rate for the North West Atlantic where K= 0.19 (Erzini, 1991). These growth rates are compared to survey data gathered by NEFSC.

1.3 White Hake

1.3.1 Length/Weight

The relationship between white hake length (cm) and weight (lbs). The data was collected during NEFSC research bottom trawl surveys from 1992 to 1999. For the autumn surveys which were conducted from Cape Hatteras, North Carolina to Nova Scotia, Canada a= 0.000004119 and b=3.1715 (Wigley et al., 2003). Winter and spring surveys were conducted from Cape Hatteras, North Carolina to the Southern Flank of George’s Bank. For the winter surveys a= 0.000001904 and b= 3.3669. For the spring surveys a= 0.000002376 and b= 3.2903.

1.3.2 Age/Length

The relationship between White Hake length and age calculated by the von Bertalanffy growth rate in two instances for the Southern Gulf of St. Lawrence in Canada where in one instance K= 0.218 and in the other K=0.106 (Clay D. & H. Clay, 1991). These growth rates are compared to survey data gathered by NEFSC.

2 Distribution of Lengths

3 Stomach Content Volume

4 Stock Assessment Reports

4.1 Commercial Landings

4.1.1 Pollock

The total commercial catch of Pollock from the Gulf of Maine (Area 5) and George’s Bank (Area 6) caught mainly by gillnet, hook/line, and trawl (Northeast Fisheries Science Center, 2010).

4.1.2 White Hake

US commercial landings (mt,calc. live) of White Hake in NAFO Subareas 5 and 6, and 464 and 465 (Northeast Fisheries Science Center, 2013).

4.1.2.1 Commercial Landings by Gear Type

4.1.3 Red Hake

US landings of red hake (mt) from the Gulf of Maine to Northern George’s Bank (northern region) and Southern George’s Bank to Mid-Atlantic Bight (southern region) (Northeast Fisheries Science Center, 2011).

4.1.3.1 Commercial Landings by Gear Type

4.2 Biomass

4.2.1 Pollock

US commercial landings (mt,calc. live) of White Hake in NAFO Subareas 5 and 6, and 464 and 465 (Northeast Fisheries Science Center, 2013).

4.2.2 White Hake

Stratified mean catch per tow in numbers and weight (kg) for White Hake from NEFSC offshore fall spring and fall research vessel bottom trawl surveys (strata 21-30,36-40) (Northeast Fisheries Science Center, 2013).

4.2.3 Red Hake

Swept area biomass red hake from the NEFSC fall and spring bottom trawl surveys in the northern and southern management regions combined (strata 1- 30, 36-40, 61-76). Estimates for 2009 were converted to Albatross units using the calibration factors at length in Table C34 (Northeast Fisheries Science Center, 2011).

4.3 Discards

4.3.1 Pollock

Discards (mt) by fleet and NAFO area (in US waters of areas 5&6). The four fleets that account for nearly all pollock discards were small-mesh otter trawl, large-mesh otter trawl, large-mesh gillnet, and extra-large mesh gillnet. Estimates of pollock discards from other fleets (longline, handline, small-mesh gillnet, scallop dredge and midwater trawls) were excluded from discard estimation because of periods with low sampling intensity and apparently low magnitude of pollock discards. Discards from the shrimp fishery were also considered to be negligible (Northeast Fisheries Science Center, 2010).

4.3.2 White Hake

White Hake discards (mt) from the northern and southern regions by gear. The discards from 1981-1988 (1991 for scallop dredge and longline) are hind- cast using the first three years of available data. The otter trawl discards are hind-cast combining mesh-sizes (Northeast Fisheries Science Center, 2013).

4.3.3 Red Hake

Red hake discards (mt) from the northern and southern regions by gear. The discards from 1981-1988 (1991 for scallop dredge and longline) are hind-cast using the first three years of available data. The otter trawl discards are hind-cast combining mesh-sizes (Northeast Fisheries Science Center, 2011).

4.4 Recruitment

4.4.1 Pollock

Recruitment was assumed to follow a Beverton-Holt functional form, with an assumed CV=0.5 for annual recruitment deviations (i.e. on log-space the standard deviation of the residuals about the stock-recruitment relationship was 0.5). Mean recruitment was around 21 million age 1 recruits. The model estimated steepness at 0.66 with a CV of 0.24 (Northeast Fisheries Science Center, 2010).

4.4.2 White Hake

See B2.2.6. for Stock-recruitment function residuals (Northeast Fisheries Science Center, 2013).

Appendix Figure B1.4 compares the stock-recruitment curves for RCp (Ricker), sensitivity 2a (Beverton-Holt) and sensitivity 2b (modified Ricker, with y estimated). See Appendix Table B1.4 Exploration of the SCAA with the final data on page 320 (Northeast Fisheries Science Center, 2013).

4.4.3 Red Hake

Note: No stock recruitment model found for red hake.

4.5 Selectivity

4.5.1 Pollock

The divergence between the NEFSC fall index selectivity and the fishery selectivity is especially pronounced towards the end of the time series. This divergence is important, as the AIM model assumes that the selectivity is the same in the fishery and the index. The sensitivity of stock status to the model estimated dome-shaped selectivities was evaluated by comparing current F and SSB estimates from the sensitivity model with flat survey selectivity for ages 6-9 to their corresponding reference points. Assuming flat survey selectivity, the model estimate of SSB2009 was 77,000 mt, which is greater than the SSBMSY proxy of 58,000 mt, so the stock would not be considered overfished. The model estimate of F5-7 in 2009, assuming flat survey selectivity, is 0.13, which is less than the corresponding F40% on ages 5-7 of 0.22, so overfishing is not occurring. It was therefore concluded that stock status is not sensitive to the shape of survey selectivity at older ages (Northeast Fisheries Science Center, 2010).

4.5.2 White Hake

The selectivities estimated from the model indicate that the autumn survey catches more younger fish than the spring while the spring catches more older fish, although both surveys have highly domed selectivities (Northeast Fisheries Science Center, 2013).

Fishery selectivities show a higher selectivity at younger ages in the first block (Northeast Fisheries Science Center, 2013).

4.5.3 Red Hake

Note: no selectivity indices found

5 References

5.1 Pollock

Erzini, K., 1991. A compilation of data on variability in length-age in marine fishes. Fisheries Stock Assessment, Title XII, Collaborative Research Support Program, University of Rhode Island. Working paper 77, 36p.

Northeast Fisheries Science Center. 2010. 50th Northeast Regional Stock Assessment Workshop (50th SAW) Assessment Report. US Dept Commer, Northeast Fish Sci Cent Ref Doc. 10-17; 844 p. Available from: National Marine Fisheries Service, 166 Water Street, Woods Hole, MA 02543-1026, or online at http://nefsc.noaa.gov/publications/

Wigley, S. E., McBride, H. M., & McHugh, N. J. (2003). Length-weight relationships for 74 fish species collected during NEFSC research vessel bottom trawl surveys, 1992-99(United States, NOAA, Northeast Fisheries Science Center). Woods Hole, MA: U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Northeast Fisheries Science Center.

5.2 Redhake

Northeast Fisheries Science Center. 2011. 51st Northeast Regional Stock Assessment Workshop (51st SAW) Assessment Report. US Dept Commer, Northeast Fish Sci Cent Ref Doc. 11-02; 856 p. Available from: National Marine Fisheries Service, 166 Water Street, Woods Hole, MA 02543-1026, or online at http://nefsc.noaa.gov/publications/

5.3 Whitehake

Clay, D. and H. Clay, 1991. Determination of age and growth of white hake (Urophycis tenuis Mitchill) from the southern Gulf of St. Lawrence, Canada (including techniques for commercial sampling). Can. Tech. Rep. Fish. Aquat. Sci. 1828. 29 p.

Northeast Fisheries Science Center. 2013. 56th Northeast Regional Stock Assessment Workshop (56th SAW) Assessment Report. US Dept Commer, Northeast Fish Sci Cent Ref Doc. 13-10; 868 p. Available from: National Marine Fisheries Service, 166 Water Street, Woods Hole, MA 02543-1026, or online at http://nefsc.noaa.gov/publications/

Wigley, S. E., McBride, H. M., & McHugh, N. J. (2003). Length-weight relationships for 74 fish species collected during NEFSC research vessel bottom trawl surveys, 1992-99(United States, NOAA, Northeast Fisheries Science Center). Woods Hole, MA: U.S. Dept. of Commerce, National Oceanic and Atmospheric Administration, National Marine Fisheries Service, Northeast Fisheries Science Center.